Question: What do the following two equations represent? $3x-3y = 5$ $3x+3y = 1$
Solution: Putting the first equation in $y = mx + b$ form gives: $3x-3y = 5$ $-3y = -3x+5$ $y = 1x - \dfrac{5}{3}$ Putting the second equation in $y = mx + b$ form gives: $3x+3y = 1$ $3y = -3x+1$ $y = -1x + \dfrac{1}{3}$ The slopes are negative inverses of each other, so the lines are perpendicular.